# Copyright (c) 2019 Tradeshift
# Copyright (c) 2020 Sarthak Mittal
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


class Data:
    def sample_generator(self):
        raise NotImplementedError

    def types(self):
        raise NotImplementedError

    def shapes(self):
        raise NotImplementedError

    def array_to_str(self, arr):
        raise NotImplementedError


class UnkDict:
    unk = '<UNK>'

    def __init__(self, items):
        if self.unk not in items:
            raise ValueError("items must contain %s", self.unk)

        self.delegate = dict([(c, i) for i, c in enumerate(items)])
        self.rdict = {i: c for c, i in self.delegate.items()}

    def __getitem__(self, item):
        if item in self.delegate:
            return self.delegate[item]
        else:
            return self.delegate[self.unk]

    def __len__(self):
        return len(self.delegate)

    def idx2key(self, idx):
        return self.rdict[idx]
